The present invention pertains to mechanical improvements to personal vehicles including self-propelled personal vehicles.
Personal vehicles, such as may be used by handicapped persons, may be self-propelled and user-guidable, and, further, may entail stabilization in one or more of the fore-aft or lateral planes, such as when no more than two wheels are in ground contact at a time. More particularly, such vehicles may include one or more clusters of wheels, with wheels in each cluster capable of being motor-driven independently of the cluster in its entirety. One example of such a vehicle is described in U.S. Pat. No. 5,701,965, which is incorporated herein by reference. Since personal vehicles operate under stringent constraints of weight and power, the features of such vehicles are typically limited to those essential to the propulsion of the vehicle, with safety left largely in the hands of the operator, and comfort largely foregone. Vehicles of this sort may be more efficiently and safely operated employing mechanical features supplementary to those described in the prior art.
In accordance with a preferred embodiment of the invention, there is provided a personal vehicle for carrying a payload including a user. The vehicle has a ground-contacting module that supports the payload and has at least one ground-contacting member. The vehicle also has a motorized drive arrangement, mounted to the ground-contacting module, that causes automatically balanced operation of the vehicle in an operating position that is unstable with respect to tipping when the motorized drive arrangement is not powered. The vehicle has a seat for supporting the user, the seat being coupled to the ground-contacting module in such a manner that the seat may be removed without the use of a tool, such as by means of a quick-disconnect assembly.
In accordance with another embodiment of the present invention, the personal vehicle has a footrest coupled to the ground-contacting module for supporting the foot of the user, where the footrest may also be decoupled from the ground-contacting module without the use of a tool. The footrest may be coupled to the ground-contacting module through the seat assembly such as by means of a mounting pin inserted in a J slot.
In accordance with another embodiment of the invention, there is provided a personal transportation vehicle having a seat back coupled to the seat assembly, the seat back being tiltable with respect to the seat assembly. The vehicle may also have a sensor arrangement that provides a signal corresponding to the tilt of the seat back. The seat back may be positionable at one of a plurality of positions provided with respect to the seat assembly, thereby positioning the CG of the user at a desired position with respect to the ground-contacting module.
In accordance with further embodiments of the invention, the personal vehicle may have at least one caster capable of being brought into engagement with the ground during operation of the vehicle. In one embodiment of the invention, motion of the caster in a direction having a vertical component is coordinated with motion of the seat assembly of the vehicle. The caster assembly may be decoupled from the ground-contacting module without the use of a tool, and may include a suspension mechanism for dampening transmission of vibration to the vehicle.
In accordance with another embodiment of the invention, the personal vehicle may have a power module disposed substantially beneath the seat assembly and contained substantially within the areal projection in the horizontal plane of the seat assembly. The personal vehicle may have a user interface module for permitting a user to command the motorized drive arrangement and a differentially frangible coupling for attaching the user interface module to the support structure.
In accordance with yet another embodiment of the invention, the personal vehicle may have a belt tensioning mechanism for tensioning a belt that transmits torque from a motor to a rotary member having an axis of rotation. The belt tensioning mechanism has a motor having a roller for engaging the belt and a cam plate. The cam plate has a slot ridge for receiving the motor, a rotation ridge disposed eccentrically with respect to the slot ridge, and a plurality of circumferential sprocket teeth. Finally, the tensioning mechanism has a transmission plate fixed with respect to the axis of rotation of the rotary member, the motor having a rotational orientation defined with respect to the transmission plate, the transmission plate having a substantially elliptical cam plate rotation shelf for receiving the cam plate rotation ridge such that a lateral position of the motor with respect to the transmission plate may be changed by rotation of the cam plate while the rotational orientation of the motor remains substantially constant.
The personal vehicle may have a self-pulling mechanism for a wheel having a tapered axle bore and a hub. The self-pulling mechanism has an axle having a taper corresponding the bore of the wheel and a threaded end, a retaining ring seated on an inside groove of the hub of the wheel, and a wheel nut having a threaded bore corresponding to the threaded end of the axle such that upon tightening the wheel is retained on the axle and upon loosening a force is applied to the retaining ring for removing the wheel from the axle.
In accordance with alternate embodiments of the invention, there is provided a vehicle for carrying a payload having a power module with left and right compartments capable of interchangeably receiving a power pack, where the respective compartments of the power module may be coupled to redundant power circuits. The personal vehicle of embodiments of the present invention may also have a handle having an adjustable extension for retention by an assistant in operating the vehicle.